Refillable fuse.



Patented De. 30,1919.

A. F. DAUM.

REHLLABLE FUSE. APPLlcAnoN FILED APR.11.1916.

luv/:

INVENTOR VVITNESSES NT FFIUE.

ALiBELT l?. BAUM, 0F PITTSBURGH, IPENNSYLVANIA.

REFILLABLE FUSE.

Application filed April 17, 1916. Serial No. 91,665.

T 0 all whom #may concern.'

Be it known that I, ALBERT F. DAUM, a citizen ot the TJnited States,residing at Pittsburgh, in the county of Allegheny and Stateof`Pennsylvania, have invented certain new anduseful Improvements in 'Reillable Fuses, of'which the 'following is a specification.

My present invention relates to improvements in rellable fuses.

Fuses of this type for commercial adoption must have certaincharacteristic fea- 1 tures to take care of Vtlie'inany conditions whichare encountered in fuse use; some of these conditions are as follows:

The fuse should be of a construction which will permit the removal ofthe blown fusible element and the insertion of a new element withoutrequiring the use of tools, since it may be necessary to make thesechanges quickly and at points where tools cannot be convenientlyobtained; the construction must be as simple aspossible to not onlyprovide for inexpert manipulation but also to permit oi' manufacture ata minimum cost; a maximum amount of metallic contact with the fusibleelement is essen; tial in order that the heat produced may be dissipatedas rapidly as possible, and also to tend to localize the point ofdisruption away from the ends of the fuse., thereby preventing damage tothe non-fusing elements', thus enabling these parte to be used continuously with the ready manipulation initially employed.

These conditions are met by the invention herein disclosed which-.inaddition provides a number ot other features among which are'the-following: y

construction adapted to provide roi' automatic indication of the blowingof the fuse; providing' limited axial movement of the parts when thefuse blows, thereby reducing expansion effects to a material extent; theprovision or a simple i'orm ot clampinnme'mber, either in unitary orbuiltnp construction, and which not only 1s removably secured to the capbut also coperates with the cap in producing the clamping1 action; theuse of a clamp-ing member ot' such form as will cooperate with the shellfor certain purposes and in such manner as will permit the cooperatingparts et the shel to be formed in simple and inexpensive manner; theprovision of a clamping member which can be readily stamped out; the useof a structure in which the cap can be quickly -removed or placed inposition 5 to provide a construction which, when applied to theknife-blade type fuse, will act as a. preventive against the use of afusible element of increased thickness; and to provide a structure whichis durable in construction and simple and eliicient in 0peration.

To these and other ends, the nature of' which will be readily understoodas the invention is hereinafter disclosed, said invention consists inthe improved construction and combination of parts, hereinafter fullydescribed, illustrated in the accompanying drawings, and moreparticularly pointed out in the appended claims.

In the accompanying drawings, in'which similar reference charactersin'diliioate similar parts in each ot' the views,-

Figure 1 is a longitudinal sectional view ofa fuse constructed inaccordance with my invention, the section being arranged to show 'theelements or sections' taken at right angles to each other.

Figs. 2, 4;, 5 and 7 are similar views showingvarious modifications.

Figs. 3 and 6 are views partly in section and partly in elevationshowing other modified forms.

Fig. 8 is a `longitudinal sectional view showing another modification.

Fig. 9 is a longitudinal sectional view showing the effect when afusible element of different thickness is employed'.

Fig. l@ is a perspectiveview of the clamping,r element shown in Figs.Tand 9.

Fig. l1l is a perspective view of the clamping element shown in Fig. 8.

Fig. 12 is a diagrammatic view indicating the eiiect ot the use ofdifferent thicknesses ot' fusible element in afuse'oi the knifeliladetype.

In the present invention, the basic idea is to provide a threadedengagement between the cap and the o posing clamping member (the capitself orming the other member), such clamping member being held againstcomplete rotation by the shell, thus connecting the cap and inner memberas a unitary structure and at the same time practicallyl dispensingwith'the use of threaded members independent of the cap but connectingthe ca and clamping member together. Coup ed with this basic idea arevarious features which will be referred to in vil@ ice,

vse

detail. In carrying out this idea certain dominant features are present.For instance, the actual threaded connection of cap and clampingmen'iber is limited circumferentially of the cap, thus dispensing withany 'requirement of the use of metallic member between the cap skirt andshell, while enabling theV use of a clamping member ot' ample size andcross-sectional area as to efficiently dissipate the heat and thusirovide a minimum damaging effect on the threads; another phase of thisheat dissipation is the use of the cap as one of the clamping members sothat the current need not reach the cap through the threaded connectionand lthe heat dissipation can exteiidfinto the cap (through the metalliccontact of the parts) independent of such threaded engagement. Thearrangement may permit of limited relative movement. of the unit in thedirection of length of the shell; it may also have means for placing thefusible element under tension or the unit maybe held from movementrelative to the shell and the latter may also be threaded to the shell.

In the drawings 20 indicates the shell formed of suitable insulatingmaterial, and which may be provided with threaded ends,

as in Fig. 6, but which is preferably free Ivfrom threading as in`theremaining views.

2l designates the cap which may vbe of any of the well-known types, ltwoof which are shown in the drawings. 22 designates the inner clampingmember, and 23 designates the fusiblev element, shown as in strip formbut which obviously could be in wire form.

As shown, member 22, in` each case is formed to engage threads on theinterior of the cap skirt, and at the same time is so -mounted withrespect to the shell as to be free from complete rotational movement inthe shell, the parts being arranged so as to prevent such rotationalmovement, as inA Figs. 5 to 9, or having a limited movement in thisdirection as in Figs. 1 to 4, it being understood that the clan'ipingmembers of Figs. 7 and 8 may/be used in connection with the shells ofFigs. l to 4, in which case such limited movement would be provided,such limited movement permitting adjustment of the' blades to a limitedextent without, affecting clamping action on the fusible element.Similarly, the unit may have a limited longitudinal movement in theshell, as in Fig. 1 or such movement may be prevented, as in Fig. 7,these movements being,

dependent on theparticular form of openings 20 formed in the shell.Y

Member 22 may have diderent forms: For instance,in Figs. l to 3, 7 and8, the member is shown somewhat H-shaped, the inner elongated ortionbeing adapted to extend into or through openings 20a, the outerelongated port-ion'resting on the end of the shell, the outerportionhaving the 'ings 20a spaced from such ends clamping surface whichopposes the cap, the limer portion acting to retain the cap againstwithdrawal from the shell excepting by a threading action.v Eitherelongated portion may carry the thread-engaging structure,

' which may be in the form of a single thread shown in Figs. 7, 9 andl0, in which it is shown as stamped out in completed form thuseliminating any requirement of a machining operation. The structure ofFigs.

8 and Il may also be stamped out and then bent over to form the extendedclamping surface. The cap is threaded coniplemental to the particularform of member employed, that. shown in Figs. 7 to 9 being of'coarsethreads to accord with the single thread of the structure of F ig. l0,this arrangement being especially' desirable by reason of its quickact-ion, a single turn of the cap being generally sutlicient .to removethe' cap or place it in clamping position.

Member 22 is placed in position before the cap is positioned, remaining`in position, the member being inserted internally of the end of theshell to permit the inner elongated portion to pass into openings 20a. If desired, the member may be especially formed to aid in such insertingmovementl by shifting the cross-connection as in Fig. 3.

In Fig. ,'the member 22 is shown with In Figs. 5 and 6, member also hasthe A outer elongated portion omitted, the member being integral Ainstructure, the member being located in slots 20b extending inwardly fromthe ends of the shell, instead of open- As this latter arrangement doesnot provide engagement between the member and shell, I prow duce thisresult in other ways. For instance, in Fig. 5 I have shown the skirt ofthe cap as carrying pins 25""adapted to extend into the openings 20A,these pins being carried,

iis

for example, by screws; in Fig. 6, I have shown the shell as threaded tocorrespond with the threads of the member. In each instance, however,the cap is held from withdrawal excepting by a threaded action.

*Shelli lmS permit -placed in position eilzlie wii i ,eeefiei ooeninge20a 'or sloie 20" are arranged d:

site and are of similar iioiin. 'lhis permits of ready formation by theuse of siutahle mechanism which enables the elined openings or slots ofan end io be placed in position at one operation, eline niateiielly re-ldueing the cost, threading beingI eliminated excepting in the forni-olfFig. Gi an opereiion of considerably greater expense.

lf dcsired.,`inember shown in Figs. 8' and l1 may be orifel h sloiJ 2;?bthrough lwhich the fusil. element may pass, but Jhis is noiJ essentiel'g 8 showing ijhe manner in "which `he fili-lele elemeniy can be hin Ehesloi o1 ont of such slot.

lf desired, l may employ for placing the fusible element under`ALension, 'using e spring monnied e-iiernally of vthe shell betweenthel sliie oi" the cap and an annular member 2?. preferably carryingsecuring members 27?; This er rangement is espeeinjf' useful Where openings 20 are elongeed lengthwise of ehe longiudinel nieven'ient of theunit oinied by the Cep, meniber 22 and the clamped portion of the 'fusiAble element; this pe Lis ehe fuse io not as an indicating fuse. l', herehis arrangement is employed, ehe spring. 26 end member. 27* aie movedioward ehe opposite end or" zhe shell end the fusible element placed inclamped position Wiih member 22heving the projecting porions of theinner elongatedportion positioned et he inner end of openings 20%,;Theand nienibef 2! ellen movedY o position io compress spring 25 and memberE?? eeeured piece. rl`he clemping aefion on @he iisidole elenieni pre--i.' sprl' o' a e nnii ifnsiole ele l, wheren fe ille uni 2o 'l1-ainoenien ol e. e .l inner ineznber which lu les e lengn ezfcepiing inFig. in which iovement-liniiiing also serves io lesions; in that ittends lo dienpt "shedA ele'sneniJ before le reaches its melting polini.

As will be readily understood, "ehe only. ac'eion required during therelling opera tion is to remove ehe Caps, insert a new 'i'iisire ehecaps io position,

' f f their posi- Jeools nired. rlhe p' .ri ie esos.v excepl;

by il men?, oi l" A is employed. in bei* or plaie on the same plane(represenlzed by line d in Fig. 12),*:Zhns placing; ehe blades inpropel? position to enter the iusebloeli. lf, however7 the fusibleelement be of an increased thickness, neither cap can be threadedsoilieiently to bring the blades inio alineinent (see lines .71 and c ofFig. l2)9 thus nieveno ing entrance. of Jehe fuse' into ehe inse block.similar result will accrue iii the ili'ieliness be decreased below thatintende'l, ilu-:earlA ing aciion cari' 'ing *ehe cai-os l nd bladealining posiion. ln eiehei' ca. ndieaiion wfould be given oi? bhe Wrongefusible elemeni' beingei'nployed, While in ille first case use oi' theincreased thickness would be prevented. Yifi/here pla);7 is permitted,the limited movement" would not aii'ect the clamping acion as themovement would be oif the entire unit.

As will be clear, a posiiive clamping tion is provided and maineinedregardless of any contracting or expansion eil'ect which may be had bythe shell, especially when made of fiber; this is due "no the i'ac, ihm,Jhe cap and member 22 are threaded izo geher, so that coniraction'oishell is ineil'eem ive, even in the forni shown in Fig. 6. l'n addition,conducting relation is noi. only hed through `he threaded conneeion butis ineinly providedthrough diiec: coniac'i oi fusible element and cap,eline relieving che hreaded eonneeeion from. den'aaging eileei-e :fine'i3-o niet-allie Contact. nd @here folie forni of Figs.. Z to isemployed, this effect is sfaill nitliei reduced by reasole`- of thesmall ammini; oi sinfaee eonact in the 'hreadedother changes andmodiicaions may he (le-- sireel er ,required to meel; the exigeneies oiuse, and l desire to be understood as reeeiiTH 'ing the 'iigli'J toIneke such changes enel modilcaeions as nieylbe 'found ne'cessaify invso im as tlie'saine may. fall Within the spirii and scope of the,invention as expressed inhe eceoinpeng ing claims.

Hei/'ing eline deseiihed my invention, Wlial1- l cleim as new is:

l. ln arelillable fuse) a shell, end .a iusi ble-element elemging non;eompiiemg en lll@ ble-element .clamping unit Comprising an end cap and asheet metal member Within and threaded to the skirt of the cap at spacedpoints circumferentially of the interior ofthe skirt. 3.'In a reillablefuse, a shell, and a fusible-element clamping unit comprising an end capand stamped-out sheet metal mem-.

ber Within and threaded to the skirt of the cap at spaced pointseireumferentially of the interior of the skirt,

4. In a refillable fruse, a shell, and a fusible element clamping unitcomprising an end cap 'and a member Within and threaded lto the skirt ofthe cap, saidl unit and shell having Cooperating means for retainingsaid member against complete-rotational movements.

5. In a refillable fuse, a shell, and a fusible-elen'lent clamping unitcomprising an end Cap and a member Within and threaded to the 'skirt ofthe cap, said unit and shell having cooperating means to permit limitedrelative movement lengthwise of the shell.

6. In a refillable fuse, a shell, a fusibleelement clamping unitcomprising an end cap and a member Within and threaded to 'the skirt ofthe cap, said shell and unit having a limited relative movementlengthwise of the shell, and means cooperating with the cap for placingthe fusible element.

under tension.

'7. In a rellable fuse, a shell, a fusibleelement clamping unitincluding a met-allie end-Cap, and tension means carried by and externalof the shell and cooperating With the eap for placing the fusibleelement under tension.

8. In a relillable fuse, a shell, a fusibleelement clamping unitincluding a metallic endap, an annlilus externalof and adjustablelengthwise of the'shell, and a Compression spring'between said cap andannulus.

9. In a efillable fuse, a shell, and a .fusible-element clamping unitcomprising inner and outer members with the inner member threaded to theskirt of the outer member, said shell and one of said clamping membershaving cooperating means to permit limitedendWise movement ot the unitrelative tothe shell.

10. In a retillable fuse, a shell, a fusibleelement clamping unitcomprising an end eap and a member within and removably secured to theskirt of the cap at spaced points eire-umferentially of the interior ofthe cap.

' 11. In a refillable fuse, a shell, and a fusible-element clampingunitcomprising an end cap and a member Within and threaded to the skirtof the cap, said shel'l` being slotted, said member having projectingpor- -tions entering said slots.

12. In a relillable fuse, a slotted shell, and a fusibleY elementclamping unit comprising an end cap and a member Within said cap andhaving projecting portions entering` said slots, said portions beingthreaded to the skirt of the ea 13. In a regllable fuse, a shell, and afusible-element clamping unit comprising an internally-threaded end cap,and a member having spaced-apart portions adapted to engage a'singlethread of the cap.

14. In a rellable fuse, a shell, and a fusible-element Clamping unitcomprising an internally-threaded end cap, and/.asubstantially1 atmember having teeth adapted to engage threads of the cap.

15. A fusible-element Clamping member formed of sheet metal and havingtoothed portions adapted nto engage the threads of an end-cap.

16. A fusible-element clamping-*member formed of sheet metal and havingtoothed the shell each unit com )risino an end-ea positionable b v athreading movement, and a member Within and to which the cap is threadedat spaced points eireumferentially 'of the interior of the cap.

19. In a reillable fuse, a shell, and fusibleelement clamping-units ateaeh end of the shell, each unit including an end-cap carrying a Contactblade, and a member positioned within and threaded to the skirt of thecap, said eaps and members being relatively positioned to limitthreading movements of the end-caps to place the blades in alinementsolely in the presence of a 'fusible element of predetermined size.

In testimony whereof, I have aliiXed my signature in the presence of tWoWitnesses.

L. H. McCann, E. M. RYAN.

